1. Field of the Invention
The present invention relates generally to aiming systems, and specifically to portable remotely-controlled aiming mechanisms for pointing firearms and other devices at an intended target, as well as video feedback components of such systems indicating the direction of aim, and audio feedback components indicating changes in the direction of aim.
2. Description of Related Art
The typical means for aiming small portable devices such as firearms, optical instruments, cameras, and spotlights, is for a human operator to aim the device by hand in the direction of the intended target, while physically supporting the device. Control feedback is provided by estimating the optimal direction of aim in advance, aiming the device as close as practical to the intended direction, and then making minor corrections to the direction in response to observed errors in targeting. Effective operation of such devices generally requires the user to aim the device accurately in a variety of conditions. However, accuracy is often degraded when the user is unable to steady the device, when the operator experiences fatigue due in part to the physical stress of operating the device, by lack of fine control in the direction of aim (particularly when making quick gross changes of aiming position), and by a variety of responses the operator may make in response to hostile environments.
Portable firearms, such as semiautomatic rifles, present special safety and operational difficulties for their operators. Because they emit single projectiles or discrete bursts of projectiles in a particular direction, rather than performing continuously, firearms do not provide continuous or real-time feedback on the current point of aim. Furthermore, because firearms impart significant inertia into their projectiles, the corresponding recoil may overcome the operator""s capacity to steady the firearm steady while firing. The recoil thus causes a slight or gross change in the direction of aim following firing, requiring re-aiming of the firearm after each projectile or round of projectiles, creating a corresponding limits to the fine control of aim that would otherwise be obtainable by iterative re-aiming. Furthermore, combat situations typically encountered by police or light infantry soldiers involve substantial physical danger for the operator, who must take defensive steps to avoid injury. Such steps greatly increase the training time required to learn how to use a firearm in hostile environments, and severely reduce the aiming accuracy and firing frequency.
Several existing technological enhancements help operators overcome accuracy and safety difficulties when aiming small portable devices. Accuracy is improved by the use to sights and spotting telescopes, by reticles, and by other pointing aids. Stability and support may be provided by steadying devices against a fixed object or by mounting devices on a tripod or other support structure. Safety may be improved by providing armor or other physical protection for the operator or, in the cases of firearms operated under hostile fire, by hiding behind protective battlements or by taking evasive maneuvers.
One way to significantly improve both stability and safety of aiming devices is to aim and operate such devices remotely rather than by direct manipulation. Remote operation systems typically involve mounting devices such as firearms on a carriage, with means to position the carriage in response to electronic control signals. An operator controls the device remotely by means of a portable hand controller. By mounting a device on a carriage rather than in the operator""s hand, and by supporting the device on a base rather than on the frame of the operator""s body, the operator ensures that the aiming position remains stationary rather than deviating over time. Video feedback may be incorporated into the aiming system so that an operator can view the target remotely on a monitor, often magnified via a telephoto lens. This enables the operator to remain at a distance from the aiming device, thereby eliminating the operator""s need to be in a direct line of sight with the target, and reducing the operator""s exposure to hostile conditions that may be present at the location of the device.
Despite the advantages noted, several critical limitations prevent remotely-controlled aiming mechanisms from achieving the desired improvements in accuracy and safety, and consequently such mechanisms have not gained widespread acceptance. First, there is a trade-off between speed and precision of operation in the positioning means. A mechanism capable of fine adjustments to aiming position is usually not capable of making quick gross movements. Mechanisms that can make quick gross movements are usually not capable of fine control. Even when a single device is capable of both rapid gross movements and precise fine control, the gross movements generally achieve only an approximate aiming position, after which fine positioning control must be accomplished, greatly reducing the speed of re-aiming the device following a gross movement or correction.
Second, limitations in eye-hand coordination, muscle control, and perception, generally prevent operators from achieving the precision, speed, or accuracy of aiming movements with a hand remote controller that they could achieve by direct manipulation of a device. Whereas operators can generally manipulate devices quickly to a new point of aim by handling the device, after a minimum of practical training, most operators are unable to operate hand control devices such as joysticks or trackballs with enough control of speed or direction to achieve comparable results.
Third, delays inherent to remote control systems cause operators to overcompensate when making a change in aiming location, thus overshooting their intended target direction. One such delay is mechanical, caused by inertial and other delays in the means of mechanically positioning devices. Another delay is the perceptual lag between the time that an aiming location is achieved and reported (via direct observation or a video signal, for example), and the time the operator becomes aware of and responds to the observed location.
Thus, it would be desirable to create a remote control aiming system for use with small portable devices that achieves accuracy, speed, and precision comparable to, or better than, that achieved by hand operation and aiming of the devices. Specifically, what is needed is an aiming system that incorporates a better system than the prior art for hand operation of remote control units, perceptual feedback of aiming location, and improvements in the means used to position the device.
In one aspect, the present invention provides a powered aiming mechanism that points a device at a target, where the device is attached to a carriage mounted on a base, and where actuators rotate the carriage on two axes in response to remote-control signals. In the described embodiment, the actuators comprise electronic servomotors that operate threaded shafts to which actuator rods are partly threadedly engaged, and which extend and retract in response to the rotation of the threaded shafts.
In other preferred embodiments each of the servomotors is an electronic stepper motor that operates the threaded shafts forward and reverse by predetermined angular increments. In the described embodiment, the electronic stepper motors may operate either by single steps or at a rate of steps ranging from zero to at least 500 steps per second.
In alternate embodiments, the device pointed by the aiming mechanism may include a sensing instrument, an illumination device, or a semiautomatic firearm. In the case where the device is a semiautomatic firearm, one embodiment is for the device to include a trigger actuator which operates the trigger of the firearm in response to a remote control signal. In one aspect, the carriage includes longitudinal slots with recoil struts so as to absorb recoil forces, and optionally further includes shock absorbing means, and further optionally includes roller cams to steady the recoil struts within the longitudinal slots. In another aspect, the invention is a remote aiming system that includes a base for engaging a mounting surface, a device connected to the base, positioning means for aiming the device along a horizontal and vertical axis, means to control the aiming of the device and to transmit the control signals, means to acquire, transmit, and display video signals of the intended aiming target. In one embodiment the video means comprise video cameras mounted to the device. In another, there are two video cameras: a low-magnification overview camera and a high-magnification aiming camera.
In another aspect, the aiming control means comprise a two-axis hand controller device, as well as signal processing means for converting the output of the hand controller device to electronic control signals used to control the actuators. In alternate embodiments, the hand controller is ajoystick, a trackball, or a pressure sensor. In various aspects of the invention, the signal processor operates such that there is a center position or a dead zone in the center of each axis of operation of the hand controller device, where displacement to either side of the center position or dead zone along one axis of control causes the system to alter the position the device along one axis of operation. Optionally, there is an additional xe2x80x9csingle step zonexe2x80x9d outside of the dead zone, where the transition into that zone causes the system to move the device by a fixed amount along one axis of operation. In one embodiment, increasing the displacement causes a corresponding increase in the speed of positioning.
In yet another aspect, the signal processor further produces audio signals in response to the operation of the aiming control means. In one embodiment, there is one audio signal for each axis of operation of the positioning means. In other embodiments, the audio signal consists of the electronic control signals used to control the actuators. In yet other embodiments, the audio signals include tones of pitches that vary in response to the aiming speed of the positioning means along each of its axes of operation.